Problem: Subtract.
Explanation: There are many ways to solve this problem. Let's see two ways we can solve it. Place Value We can think in terms of hundredths: $\begin{aligned} &\phantom{=}38.4 - 6.57\\\\ &=38.40 - 6.57\\\\ &=3{,}840\text{ hundredths} - 657\text{ hundredths}\\\\ &=3{,}183\text{ hundredths}\\\\ &=31.83 \end{aligned}$ Place value table Let's line up the numbers by their decimal places. Tens Ones $.$ Tenths Hundredths ${3}$ ${8}$ $.$ ${4}$ $0$ $6$ $.$ ${5}$ $7$ Now, let's subtract each place value column. Tens Ones $.$ Tenths Hundredths ${3}$ $\overset{7}{\cancel{8}}$ $.$ $\overset{13}{\cancel{4}}$ $\overset{10}{\cancel{0}}$ $-$ $6$ $.$ ${5}$ $7$ $\underline{~~~~}$ $\underline{~~~~}$ $\underline{~~~~}$ $\underline{~~~~}$ $3$ $1$ $.$ $8$ $3$ $31.83 = 38.4 - 6.57$